Summary

The biggest study so far of the large-scale structure of the universe—a survey of 26 million galaxies that traced the forces shaping the universe over cosmic time—reveals the effects of dark energy, the mysterious pressure causing space to expand faster and faster. The survey finds about the same total amount of dark energy as the gold standard in assessing this cosmic recipe: precision maps of the nearly 14-billion-year-old cosmic microwave background that forms the backdrop of the universe. But the new survey and other techniques are now allowing astronomers to watch how dark energy plays out over time. Their goal: to see whether it changes.